Association Between Helicopter vs Ground Emergency Medical Services and Survival for Adults With Major Trauma.

JAMA. 2012 Apr 18;307(15):1602-10

This study adds to the recent body of literature which suggests that there exists a cohort of the most-sick major trauma patients on whom utilization of HEMS confers a survival advantage. The authors report numbers needed to treat (transported by HEMS) as 65 and 69 to save one life, for patients taken to Level 1 and Level 2 trauma centers, respectively.

It would be hard if not impossible to conduct a randomized prospective study of HEMS vs. ground EMS for poly-trauma. Thus, past studies have typically relied on retrospective database review, or have used the “before and after” approach (HEMS being the intervention added or taken away in a region).

The authors in this retrospective cohort study have undertaken a rigorous statistical analysis of over two hundred thousand patients who fit the selection criteria, using 2007-2009 data from the ACS National Trauma Data Bank. They found that “In the propensity score–matched multivariable regression model, for patients transported to level I [and II] trauma centers, helicopter transport was associated with an improved odds of survival compared with ground transport.” (OR 1.16, 95% CI, 1.14-1.17 for Level I).

Along with other similar research, this study speaks to the larger and controversial topic of “appropriate HEMS utilization”, with the term appropriate being the subject of opinion and debate. The issue revolves around three overlapping considerations – 1) existence of any true benefit of HEMS for a patient population over ground EMS, 2) ethically sound justification of HEMS cost (if #1 is satisfied) vs. extent of the benefit, and 3) which component of HEMS services (crew expertise, transport time, transport destination) contributes the most – and if it may be reached via an alternative (EMS system re-design, ground EMS improvement, etc.).

While the answers are unclear even after a most thorough review of over 30 years of literature, it is important to both have an informed opinion at present, and to maintain an open mind towards new studies undoubtedly yet to come.

J Trauma Acute Care Surg. 2013 May;74(5):1207-1214

Surprisingly, the role of prehospital crystalloid resuscitation for those patients with severe blunt trauma is still unclear. This well done study hopes to improve our understanding of the best approach to these patients.

The optimum management of prehospital crystalloid for severe blunt trauma patients is unclear.

This is a multicenter prospective cohort study of blunt injured adults with hemorrhagic shock. This was defined as the presence of prehospital or emergency department hypotension (systolic blood pressure [SBP]

This study examined the effect on mortality and on the development of coagulopathy. Among those severe trauma patients who survive the first few hours of care, the development of coagulopathy and subsequent multi organ failure often lead to death.

A large number of severe blunt trauma patients who survive the first few hours later succumb to complications of coagulopathy.

Standard operating procedures were developed and implemented across all institutional centers to minimize variation in post injury care. Demographics, injury characteristics, resuscitation requirements, and outcomes were compared. Prehospital crystalloid volume was defined as High when more than 500 mL was given.

Among blunt trauma patients without prehospital hypotension, giving more than 500 mL of crystalloid more than doubled mortality and coagulopathy.

In subjects without prehospital hypotension, HIGH (>500 mL) crystalloid was associated with an increase in the risk of mortality (hazard ratio, 2.5; p < 0.01) and worsened acute coagulopathy (odds ratio [OR], 2.2; p = 0.04). When separated out into quartiles, it was demonstrated that the more fluid that was given, the worse the outcome.

In 2006, Canadian researchers studied time to thrombolysis saved by initiating this intervention pre-hospital, based on Canadian Advanced Care Paramedics (ACPs) interpretation of EKGs. Results showed 95% accuracy in STEMI recognition, if compared with a physician’s. N of 63. (Le May, et al. CJEM)

A Canadian Primary Care Paramedic is closest to a US Advanced EMT (AEMT) in terms of scope of practice. I am not aware of published US studies regarding pre-hospital STEMI recognition by EMTs or AEMTs (even after additional ECG training).

There may not yet be a clear consensus as to the acceptable rate of false positives, when it comes to pre-hospital STEMI activation by EMS. Studies examining accuracy of ER physicians also report variable numbers – 5.2% unnecessary cath activation (Kontos, et al, Ann Emerg Med, 2010); 9-14%, depending on false positive definition (Larson et al, JAMA 2007). What should be the correct reference standard for EMS (without tele-ECG capability)?

Finally, the study reports only 2 patients out of 134 initially assessed as stable, who would have required ACLS interventions pre-hospital, or upon arrival to hospital. However, this may be related to the low N or chance alone.

Ryan D, Craig AM, Turner L, Verbeek PR.

Prehosp Emerg Care. 2012 Apr;17(2):181-6.

This very simple study examined the rate of prehospital clinical complications of patients with a confirmed STEMI.

Among those patients who were diagnosed at home and transported to the hospital, 27% of these patients developed a significant adverse clinical event. The most common events were sinus bradycardia (57 out of 342), hypotension (52 out of 342), or cardiac arrest (13 out of 342).

27% of prehospital STEMI patients will have a serious adverse event while en route to the hospital

Sinus Bradycardia 16%

Hypotension 15%

Cardiac Arrest 6%

Among those patients with a STEMI that are being transferred from one hospital to another, the rate of significant adverse clinical events was much lower at 6.2%. The most common events were sinus bradycardia (3 out of 145), and hypotension (7 out of 145). None in this group developed cardiac arrest. It is unclear why this group would be so different from the home diagnosed patients. They could have improved with treatment or self selected by presenting as a walk in patient.

Take Home Point

Suspected STEMI patients should have a second medic in the ambulance if at all possible due to the high rate of adverse clinical events.

Family presence during cardiopulmonary resuscitation

Jabre P, Belpomme V, et al

N Engl J Med. 2013 Mar 14;368(11):1008-18

This is the first study to ever methodically examine of the effect of our actions on the families of cardiac arrest victims. This is a prospective cluster-randomized control study that wanted to see if actively encouraging the family to be present for the resuscitation of their loved one would be helpful to reduce symptoms of PTSD and depression at 90 days.

Studied the effect of our actions on surviving family members of cardiac arrest victims

French ambulances contain a physician and a nurse

PTSD and Depression of the family members were measured at 90 days

This study was done in France and the ambulance crew consisted of a physician, nurse, and a driver. There were fifteen ambulance units that were assigned to either the intervention group or usual care. The intervention included having one of the team members systematically ask the family members if they would like to be present during the resuscitation.
The family members were contacted by phone 90 days after the initial incident and were asked about PTSD and depressive symptoms using two validated scales (Impact of Event Scale and the Hospital Anxiety and Depression Scale).
An intent-to-treat analysis was performed on the outcomes. Keep in mind that not everyone who was offered a viewing option did so. Also, some of the usual care group also did view the resuscitation.

The frequency of PTSD was significantly higher than the control group. (OR 1.7; CI 1.2 to 2.5, P=0.004)

The frequency of PTSD was significantly higher among those who did not witness the arrest as compared to those that did. (OR 1.6; CI 1.1 to 2.5 p=0.02)

When offered, more family members observed resuscitation (79% vs 43%).

Family Members were 60-70% less likely to suffer symptoms of PTSD if they witnessed the cardiac arrest.

There were similar lower rates of anxiety and depression among those who witnessed the cardiac arrest.

There was difference in the functional outcomes of the cardiac arrests or the stress that the health care providers experienced.

Wonky Research Points

Cluster randomized controlled study
Most randomized studies are randomized by the individual patient. Once a patient is identified, then randomization occurs. This is considered superior to other types of randomization. Cluster randomization means that some other type of organization, geographical etc. is used. In this study, half of the ambulances were randomized to intervention group. Thus one set of ambulances always enrolled family members into this study while a comparable group of other ambulances did not.

Intent to Treat Analysis

Certain treatments don’t always stick or work. For example, a particular antibiotic might work well but cause 25% of the patients to vomit the active drug. An interested pharmaceutical company would like to remove these 25% from analysis and demonstrate better outcomes. But most current studies would use an intent-to-treat analysis and since we intended to treat those patients that vomited, then they would be included.
This study offered the option to view the resuscitation in the intervention group but not all of the family members took them up on the offer. This intent-to-treat analysis demonstrated an effect on rates of PTSD suggesting that it was a very robust difference.

Good Points about this study

Prespecitve, randomized

Use of validated scales for measuring of PTSD and Depression

Intent-to-treat analysis

Problems with this study

Cluster Randomization

Is this generalizable to a paramedic system? (remember there were MD’s an a nurse on the ambulance.)

Non validated scale to measure stress of the medical team.

Encouraging family members to be present for the resuscitation will decrease their PTSD and depression symptoms.

Compared IV t-PA vs endovascular treatment

These two studies compared the use of IV t-PA versus the use of various endovascular devices to remove the clot or direct intra-arterial t-PA in higher concentrations directly at the thrombotic lesions.

Both of these studies demonstrated that when compared head to head, there was no difference in functionality or mortality between the two methods.

No functional differences in outcomes

Why should the prehospital folks care?

Many hospitals are moving toward having a neuro-interventionalist available to direct a catheter to dissolve or remove the clot from culprit lesion. They have demonstrated improved flow and other process improvements and were tantalizing in their potential promise in this still dismal disease. This could drive the need for comprehensive stroke centers similar to our STEMI system.

It was hoped and feared that this resource intensive method would be substantially better and would drive the need for comprehensive stroke centers similar to our STEMI system.

Death knell for comprehensive stroke centers

These two studies drove a large stake in the heart of the concept of comprehensive stroke centers. There will be a steady search for subgroups that do better such as late presenters or those with other contraindications for systemic t-PA.

As a health system, our successes in stroke treatment have been very modest as compared to STEMI care. For every 100 suspected strokes presenting to a primary stroke center, only 9-30% of cases receive t-PA.

For every 100 suspected strokes presenting to a primary stroke center, only 9-30% of cases receive t-PA.

Many are excluded for a large variety of reasons such as time of onset, hemorrhagic stroke, and other contraindications. But there is still a large variation among hospitals in this rate. This should be a focus of each hospital’s QI prgram.

Stroke Systems have not shown any improvement in the rate of t-PA administration.

Hasegawa K, Hiraide A, Chang Y, Brown DF.

JAMA. 2013 Jan 16;309(3):257-66. doi: 10.1001/jama.2012.187612.

This will be an important study with a lot of implications for prehospital care for a number of reasons.

Prehospital Cardiac Arrest research has increased in amount and improved in quality over the last 5 years.

Most of these studies have come from prospectively designed registries such as this study.

Japan and Korea have both developed country wide registries.

Resuscitation Outcomes Consortium and the Cardiac Arrest Registry to Enhance Survival (CARES) are two examples in the US.

Long term survival with good neurologic status (and not just ROSC or survival to discharge) has become the standard measurement.

ACLS has relied on more and more of these registry studies to drive their clinical changes. Randomized controlled studies will always be the gold standard but are difficult and expensive to accomplish.

Japan as a country has taken an aggressive stance to improve outcomes in cardiac arrest. This has been manifested as a huge increase in the number of available public AED’s, improvements in EMS and hospital care, as well as a nationwide registry with one month survival outcomes for all cardiac arrest patients.

As they make improvements to their EMS system, Japan is asking questions about the utility of advanced airway management in out of hospital cardiac arrest patients. The usual EMS crew has 3 personnel with one trained to lead a cardiac arrest, place an IV line, and use an AED. Some agencies allowed the use of supraglottic airways (LMA or combitube) and others allowed with special training, the placement of endotracheal intubation. This ET training consisted of 62 hours of training and a minimum of 30 supervised intubations in an operating room.

6% with an ET tube

37% with a supraglottic airway

The overall survival rate was this low because they included both cardiac and non cardiac causes.

The advanced airway group was not just a little worse but a lot worse.

This difference persisted even when other variables were accounted for.

This persisted even when they teased out the ET tubes and the supraglottic airways.

Why should this be the case? With such a high use of supraglottic airway devices, it should not be misplacement of the tube.

Previous studies have clearly demonstrated that almost all humans have the propensity to hyperventilate almost all of the time in these high profile cases. Hyperoxia and hyperventilation have both been demonstrated to worsen outcomes in these patients.

The State of Arizona is beginning training for all of their medics to limit the common and deleterious effects of hyperventilation in head injury patients.

Should we be doing this training for all of our airway patients?

Should we have prehospital ventilators to remove hyperventilation?

In the past, it has been very difficult to propose the prospective randomized study of airway versus BVM in cardiac arrest. This study generates enough equipoise of this clinical question to make the argument for this future study more likely to be funded.

Determining Risk for Out-of-Hospital Cardiac Arrest by Location Type in a Canadian Urban Setting to Guide Future Public Access Defibrillator Placement

Annals of Emergency Medicine 2013

Automatic External Defibrillators can be life saving when readily available for out of hospital cardiac arrests but they have been used in only a small percentage of total cardiac arrests in the best of implementations.

AED’s can be life saving

AED’s are used in a small minority of cardiac arrest cases

The location of AED’s is usually based on availability and political and emotional arguments

This study looks at the locations of 600 or so cardiac arrest cases that occurred in public. The top 5 locations categories by annual out of hospital cardiac arrests per site. They calculated the number of sites required to Yield 1 OHCA per year.

Type of location

# needed for 1 OHCA per year

Race track

2

Jail

2

Hotel/Motel

7

Hostel/Shelter

8

Convention Center

10

Rail Station

12

Golf Course

13

Sports Arena

19

Shopping Mall

20

School

72

This study mentioned that the majority of AED’s in this Canadian city were in their schools.

So we would have to place 72 AED’s in schools to have it used on one person per year. This study suggests that these other public areas might be better locations for these devices.

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